Fallon admitted he was even a little nervous interviewing the actor behind the Man of Steel. The reason? “I’d never even come close to having an arm that is close to the size of your arm,” he said. “Your arm is the size of my leg.”

Cavill admitted his busy filming schedule has him hitting the gym often, since pre-production for the new Justice League: Part 1 begins in January. (Zack Snyder’s superhero epic, the DC answer to Disney/Marvel’s Avengers franchise, is set to hit theaters in November 2017.)

When the two were discussing Cavill’s movie The Man From U.N.C.L.E., which opens Friday, Fallon even let a little spoiler slip: It turns out a certain British soccer legend-turned-model even makes a brief cameo in Guy Ritchie’s comedy/spy thriller. (We won’t ruin it for you.)

Speaking of spoilers, Fallon let his viewers in on a little secret during his opening monologue.